This invention involves a seat adjuster, more particularly, a rail and bearing assembly for the slide mechanism of an adjustably positioned vehicle seat.
Automotive seats have long been designed for mounting on an adjuster so that the seat can be adjustably positioned between fore and aft locations to meet the occupant's convenience. The combination of the adjuster assembly and the seat assembly is fairly complex and can be costly to manufacture. Several mechanisms have been used to perform the adjuster function, the most common of which includes a pair of stationary or guide rails mounted to the vehicle that engage a pair of complementary moving or slide rails connected to the seat. This type of arrangement adequately performs the major functions required of an adjuster mechanism. First and foremost, when equipped with a slide lock it generally holds the seat securely in position within the vehicle. Second the mechanism allows the seat to slide forwardly and rearwardly. Additionally, the channel construction can be formed relatively inexpensively.
As automobiles evolve however, new considerations come into play. More efficient utilization of the space within a vehicle is now required. The adjuster mechanism now is preferably amenable to both manual and power operation. A lower movement effort is preferable, but must be achieved without sacrificing structural stability. The cost of producing a mechanism has become an increasing factor in design as has the size and weight of the mechanism. Finally, with the development of anchoring seat belts to the seat assembly rather than to the vehicle itself, greater strength is required of the adjuster mechanism.
A variety of efforts to design mechanisms meeting many of the above requirements have been made. Mechanisms have been developed using roll formed sheet metal for the rails as well as others using extruded metal rails. Numerous rail configurations and types of bearing arrangements have been used to provide properly functioning seat adjusters. There remains a need however, for an adjuster with low and consistent slide effort requirements, that is relatively compact in size, has high stability, is capable of mounting on the rocker and center tunnel of a vehicle floor and can be relatively inexpensively fabricated from sheet metal.